An answer to a question of Kegel on sums of rings
Printed: Mar 1998
We construct a ring $R$ which is a sum of two subrings
$A$ and $B$ such that the Levitzki radical of $R$ does not
contain any of the hyperannihilators of $A$ and $B$. This
answers an open question asked by Kegel in 1964.
16N40 - Nil and nilpotent radicals, sets, ideals, rings
16N60 - Prime and semiprime rings [See also 16D60, 16U10]